Site-built trusses- always recommend a structural engineer?

[Marcel R. Cyr]

King post truss field built.

Not to old, cause the plywood gussets are nailed with an air nailer.

King post trusses were limited to 16' span, first thing to check is bearing under the king post. It might have been built like this for erection only.

Gussets in the late sixties and early 70's would have been 5/8" plywood and not 1/2 like appears to be here.
Nails would have been 8 penny and clinched.

Also the picture shows very poor attempt on the rafter tail extensions.

What is the age of the building?

[Randy L. Mayo, PE]

Ken

Here is an example of an attempt to build a home made truss. One of the key concepts is the arrangement of the web members should form triangles. If you look down the truss you see a vertical web all by itself. This truss went out over a porch and that vertical web member rested on the exterior wall of the house. The typical triangle pattern truss web members make stiffens the entire truss by distributing the forces. If you interrupt this triangle pattern by a poor design or a broken member forces are not distributed properly and #$@! happens like this photo.

[Marcel R. Cyr]

That's a good picture and example Randy of a framer not knowing the design concept of a wood truss design nor how it reacts.

Chord placement are totally wrong and rafter should have been a 2x6 if in a snow load area.

[Kenton H. Shepard, CMI]

That's the worst attempt at truss design I've ever seen, Randy!